Vibrating pipette probe mixer

ABSTRACT

A vibrating pipette probe mixer is disclosed having means to vibrate the pipette so that when delivering extremely small quantities of liquid, accurate mixing and dispensing is achieved. The vibrating means may be either a mechanical vibrator attached to the pipette by a stiff wire or a fluidic oscillator attached to the pipette by opposing disc shaped diaphragms.

United States Patent Nishi et al.

1451 Dec. 25, 1973 [5 VIBRATING PIPETTE PROBE MIXER 3,476,518 [H1969Jungner 73/4254 P x [75] Inventors: Hiroshi H. Nishi; Charles McCarthy,

both of Rockville, Md. OTHER PUBLICATIONS {73] Assignee: The UnitedStates of America as Technilab Instruments, Pipet Shaker, 1964.

represented by the Secretary of the Department of Health, EducationPrzmary Exammer-l-larvey C. Hornsby and welfare washmgton AssistantExaminer-Alan l. Cantor Filedi J y 1972 AtlomeyBrowdy and Neimark [211Appl. No.: 272,144

52 us. c1. 259/19, 73/4254 P, 222/198, [57] ABSTMCT 222/200" 959/ Avibrating pipette probe mixer is disclosed having 51 11 c1. B01f 11/00,BOlf 15/02 means to vibrate the pipette so that when delivering [58]Fleld of Search 73/4254 P; 259 extremely small quantities of iq accuratemixing 259/4, 19, 72, 2 1 113, 9 42, 431 and dispensing is achieved. Thevibrating means may 222/161 23/259 141/72 be either a mechanicalvibrator attached to the pipette by a stiff wire or a fluidic oscillatorattached to the pi- [56] References Cited pette by opposing disc shapeddiaphragms.

UNITED STATES PATENTS 2,732,099 1/1956 Davis 222/203 X 6 Claims, 4Drawing Figures IQ/// v V-IBRATING PIPETTE PROBE MIXER FIELD OF THEINVENTION The present invention relates to a vibrating pipette probemixer and more particularly to an apparatus for dispensing and mixingmicroliter quantities of solution for use in ultra-micro chemicalanalyses.

BACKGROUND OF THE INVENTION Often in the fields of chemistry andmedicine, it is necessary to deal with microliter quantities ofsolution. This is very important in blood analyses in infants andchildren, for example. When conducting such ultramicro chemicalanalyses, the chemist or lab technician must utilize small vessels, forexample those as small as several millimeters I.D. Furthermore,solutions must be mixed in very small proportions. It is very difficultto accurately dispense such microliter quantities of solution and it isfurthermore difficult to achieve proper mixing of one solution which isadded to another. These problems make automated analytical systems forultra-micro chemical analyses impractical to achieve.

SUMMARY OF THE INVENTION It is, accordingly, an object of the presentinvention to obviate the above-mentioned problems of the prior art. Itis a further object of the present invention to provide a vibratingpipette probe mixer for the simultaneous dispensing and mixing ofmicroliter quantities of solutions in one operation.

Briefly, the present invention consists of a pipette probe, preferablymade of polyethylene or teflon tubing drawn to a fine tip, which isconnected either directly or indirectly to a variable oscillatingdevice. The pipette probe is connected to a source of solution by aflexible connector. The amplitude of the vibration to the probe ispreferably adjustable to accommodate the amount of mixture and the sizeof the raction vessel for optimum mixing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view of thevibrating pipette probe mixer in accordance with the present invention.

FIG. 2 is a plan view partly in cross section along line 2-2 of FIG. 1.

FIG. 3 is an elevational view of an alternate embodiment of thevibrating pipette probe mixer of the present invention.

FIG. 4 is a sectional view partly in schematic form along line 44 ofFIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, pipette isjoined by a flexible connector 13 to a source of solution 14. Thepipette is connected to and supported by support by means of a bracket9. The probe 10 is connected by means of a stiff wire 11 to a variableoscillating device 12. The wire 11 passes through an aperture in thesupport 15 and the oscillating device 12 is also supported by support 15by means of suitable bracket 16. The variable oscillating device 12 maybe a magnetic solenoid, an electronic rectifier, or any other suitableoscillating systern. Preferably the amplitude of the oscillator should65 be variable and controllable. In FIG. 1, rheostat or potentiometer 17is connected by wires 19 to oscillator 12. The rheostat 17 controls theamplitude of the oscillations of oscillator 12. The rheostat 17 is alsosuitably attached to support 15 as by bracket 18.

In operation, the entire system shown in FIG. 1 may be part of a largerautomated chemical analytical system. The support 15 may beautomatically controlled to carry the vibrating pipette 10 to a seriesof different reaction vessels 8 for adding microliter quantities ofsolutions to each reaction vessel while simultaneously mixing theliquids therein. The prescribed amounts of fluid leaving the pipetteprobe in a stream is dispersed into the liquid in the reaction vessel 8by the action of the rapidly moving probe tip. The solution supply tothe probe 10 may also be automatically controlled to dispense onlypredetermined amounts of solution. The outer lower surface of the probe10 may be coated with silicone grease or some similar agent in order tocreate a hydrophobic effect thereon and thus keep any solution fromclinging to the probe after removal from the reaction vessel 8. A cyclefrequency has been found to be suitable for the oscillator 12.

An alternate method of vibrating the pipette is shown in FIGS. 3 and 4.The pipette 10. passes between two disc shaped diaphragms 20 which aresuitably attached as by rubber cement, for example, to supports 23.Supports 23 are connected to rigid tubes 21 and 24. Air pressure lines25 and 26 pass through tubes 21 and 24 and supports 23 to communicatewith the inside of diaphragms 20. The air pressure lines 25 and 26 areconnected to a suitable astable fluidic oscillator 22 which is in turnconnected to an air supply at 23. The air pressure is controlled by theoscillator 22 to alternate between the two lines 25 and 26 in order toalternately cause the inflation of each of the diaphragms 20. Thealternation of the inflation of diaphragms 20 cause the pipette 10 to bevibrated.

The outstanding features of the vibrating pipette probe mixer are itsability to utilize small vessels, for example, those as small as severalmillimeters I-.D., and to mix solutions in any proportion and order,e.g. 1 microliter into 300 microliters or 300 microliters into 1microliter, without carryover of solution in successive dilutions.

It will be obvious to those skilled in the art that various changes maybe made without departing from the scope of the invention and theinvention is not to be considered limited to what is shown in thedrawings and described in the specification.

What is claimed is:

1. In a pipette for dispensing microliter quantities of solutionconnected to a source of solution, the improvement comprising:

vibrating means connected to said pipette for causing the oscillation ofsaid pipette to achieve simultaneous dispensing and mixing of saidmicroliter quantities of solution.

2. A pipette in accordance with claim 1 wherein:

said vibrating means comprises a mechanical oscillating device and astiff wire wherein said wire connects said pipette with said oscillatingdevice.

3. A pipette in accordance with claim 2 wherein:

said oscillating device comprises a magnetic solenoid or an electronicrectifier.

4. A pipette in accordance with claim 1 wherein said vibrating meanscomprises: air pressure lines; inflatable diaphragms connected to saidair pressure lines and abutting said pipette on opposite sides thereof;and fluidic oscillator means for alternately supplying air pressurethrough said air pressure lines to cause inflation ofeach of saiddiaphragms, the alternate inflation of said diaphragms causing saidpipette to be vibrated.

a flexible connector means for connecting said pi-' pette with saidsource of solution. 6. A pipette in accordance with claim 1 wherein saidvibrating means includes means for varying the ampli- 5. A pipette inaccordance with claim 1 further in- 5 tude of oscillation.

eluding:

1. In a pipette for dispensing microliter quantities of solutionconnected to a source of solution, the improvement comprising: vibratingmeans connected to said pipette for causing the oscillation of saidpipette to achieve simultaneous dispensing and mixing of said microliterquantities of solution.
 2. A pipette in accordance with claim 1 wherein:said vibrating means comprises a mechanical oscillating device and astiff wire wherein said wire connects said pipette with said oscillatingdevice.
 3. A pipette in accordance with claim 2 wherein: saidoscillating device comprises a magnetic solenoid or an electronicrectifier.
 4. A pipette in accordance with claim 1 wherein saidvibrating means comprises: air pressure lines; inflatable diaphragmsconnected to said air pressure lines and abutting said pipette onopposite sides thereof; and fluidic oscillator means for alternatelysupplying air pressure through said air pressure lines to causeinflation of each of said diaphragms, the alternate inflation of saiddiaphragms causing said pipette to be vibrated.
 5. A pipette inaccordance with claim 1 further including: a flexible connector meansfor connecting said pipette with said source of solution.
 6. A pipettein accordance with claim 1 wherein said vibrating meanS includes meansfor varying the amplitude of oscillation.